diff options
Diffstat (limited to 'cloudinit/util.py')
| -rw-r--r-- | cloudinit/util.py | 38 |
1 files changed, 34 insertions, 4 deletions
diff --git a/cloudinit/util.py b/cloudinit/util.py index 769f3425..4e0a72db 100644 --- a/cloudinit/util.py +++ b/cloudinit/util.py @@ -359,7 +359,7 @@ def find_modules(root_dir): def multi_log(text, console=True, stderr=True, - log=None, log_level=logging.DEBUG): + log=None, log_level=logging.DEBUG, fallback_to_stdout=True): if stderr: sys.stderr.write(text) if console: @@ -368,7 +368,7 @@ def multi_log(text, console=True, stderr=True, with open(conpath, 'w') as wfh: wfh.write(text) wfh.flush() - else: + elif fallback_to_stdout: # A container may lack /dev/console (arguably a container bug). If # it does not exist, then write output to stdout. this will result # in duplicate stderr and stdout messages if stderr was True. @@ -623,6 +623,26 @@ def redirect_output(outfmt, errfmt, o_out=None, o_err=None): if not o_err: o_err = sys.stderr + # pylint: disable=subprocess-popen-preexec-fn + def set_subprocess_umask_and_gid(): + """Reconfigure umask and group ID to create output files securely. + + This is passed to subprocess.Popen as preexec_fn, so it is executed in + the context of the newly-created process. It: + + * sets the umask of the process so created files aren't world-readable + * if an adm group exists in the system, sets that as the process' GID + (so that the created file(s) are owned by root:adm) + """ + os.umask(0o037) + try: + group_id = grp.getgrnam("adm").gr_gid + except KeyError: + # No adm group, don't set a group + pass + else: + os.setgid(group_id) + if outfmt: LOG.debug("Redirecting %s to %s", o_out, outfmt) (mode, arg) = outfmt.split(" ", 1) @@ -632,7 +652,12 @@ def redirect_output(outfmt, errfmt, o_out=None, o_err=None): owith = "wb" new_fp = open(arg, owith) elif mode == "|": - proc = subprocess.Popen(arg, shell=True, stdin=subprocess.PIPE) + proc = subprocess.Popen( + arg, + shell=True, + stdin=subprocess.PIPE, + preexec_fn=set_subprocess_umask_and_gid, + ) new_fp = proc.stdin else: raise TypeError("Invalid type for output format: %s" % outfmt) @@ -654,7 +679,12 @@ def redirect_output(outfmt, errfmt, o_out=None, o_err=None): owith = "wb" new_fp = open(arg, owith) elif mode == "|": - proc = subprocess.Popen(arg, shell=True, stdin=subprocess.PIPE) + proc = subprocess.Popen( + arg, + shell=True, + stdin=subprocess.PIPE, + preexec_fn=set_subprocess_umask_and_gid, + ) new_fp = proc.stdin else: raise TypeError("Invalid type for error format: %s" % errfmt) |